.main-container {
    display: flex;
    width: 1600px;
    height: 900px;
}


.left {
    background-color: aqua;
    color: white;
    padding: 10px 20px;
    display: flex;
    align-items: center;
    width: 30%;
    height: 100%;
    float: left;
}
.left h2{
    font-size: 40px;
    color: black;
    text-align: center;
}
.middle{
    background-color:gainsboro;
    
    padding: 10px 20px;
    display: flex;
    align-items: center;
    width:20% ;
    height: 100%;
    position: relative;
}
.middle .main{
    position: absolute;
    top: 0;
    left: 0;
    width:20% ;
    height: 50%;
}
.middle .main .set_li{
    padding: 10px 10px;
    display: block;
    width:270px;
    height: 20px;

    
    background:gainsboro;
  
    text-align: center;
  
}

.middle .set_li a{
    text-decoration: none;
    color: black;
    background:gainsboro;
  
}
.right {
    flex: 1;
    padding: 50px;
    width: 800px;
    height: 100%;
}

.right .content{
    width:1200px;
    height: 100%;

}